I might be able to help there. I've been refurbishing a stack of laptops recently and have had to write a few off.

Also, when you say your !GHz board died, what exactly was the problem with it? The G4 boards seemed to have a similar issue to the G3s where the would lose video. Thing is, the G3s would boot up regardless, the G4s with the issue do not. With the exception of the last of line 1.42GHz 14" and 1.33GHz 12" boards, I can fix the video issue issues on G4 iBook boards. If yours has that problem, I'd refurbish it for $50 labour and you pay shipping (I am in the UK This offer is open to anyone else who has a G4 board needing the fix). I can only fix the video issue, so bad RAM/VRAM or any power issues or any other fault I cannot help with.
Symptoms for the G4 video fault are predominantly a completely black screen, caps lock light comes on when pressed, sometimes the fan stays on full, and pressing the power button once does not shut it down. You have to hold the power button down for a few seconds to power off (I think some needed battery and AC pulled). Units which are on the way out may have the issue come and go. You can test for it by squeezing (below the HD - don't squeeze too hard, just like the G3s) when you power on. If the video comes back on, I can fix it.